There are many material working requirements where a power tool must be located relative to a surface to be worked and it is not possible to accurately affix the tool relative to the surface by conventional means such as clamps and the like. It can be appreciated that this is especially true in situations where, for example, a large planar surface is being machined at a central location and it would be inconvenient to provide a large clamping jig to accurately and securely position the tool relative to the planar surface. This is especially true for large metal, concrete or tiled surfaces.
In the past this problem has been partially solved by using material working tools which have bases which include electromagnets. The tool can be accurately positioned and then the electromagnet turned on to secure the tool to the working surface so that the material working procedure can commence. While ideal for steel and other ferrous materials, such tools will not work with, for example, aluminum and other non-ferrous materials.
One solution that has been used in the past for drilling precision holes in aluminum and the like is to drill several holes in the aluminum which are of a nonprecise nature. Bolts or other fasteners are then mounted through the holes and are used to secure a steel plate to the aluminum structure. Then the magnetic base of a material working tool can be secured to the steel plate and the precision machining can be accomplished. After this is completed, the bores through which the steel plate was secured are filled with aluminum. Quite naturally such a process is time-consuming and expensive.
Another approach to this problem is through the use of a vacuum base to which the material working tool can be secured. The base is placed on the working surface and a vacuum is generated in the base to secure the tool to the working surface. Generally such devices include one or more flexible rubber cups which form vacuum cavities. The cups can deform and conform to the working surface. While such a base can be fastened to a number of surfaces including non-ferrous metal surfaces as well as ceramic, plastic and glass surfaces, it has been found that such a base does not allow for accurate positioning of the material working tool during the material working process as the tool is allowed to vibrate and move excessively. Some such devices use stabilizing points which are located adjacent to the suction cups. However, these stabilizing points have proven ineffective in aiding in the accurate positioning of the material working tool relative to the working surface.
Accordingly there is a need to provide a material working tool which includes a base and which can be secured accurately relative to a work surface.